Brake



March '15 1927. I

. R. s. ,sAN FORD BRAKE Filed April '7,

-INVENTOR I RoY S. SANFORD ATTORNEY Patented Mar. .15, 1927.-

' UNITED STATES 1,620,921 PATENT. OFFICE.

BOY s. SANFORD, or sou'rn BEND, INDIANA, ASSIGNOR T iammrx BRAKEcomramr,

' or cmcaeo, ILLmoIs, ACORPORATION or ILLINOIS.

BRAKE.

p This invention relates to brakes, and is illustrated as embodied in aninternal expanding automobile brake. An object of the invention 'is toprovide a simple brake of the servo type in which all of the shoes arefully effective in either direction of rotation of the brake drum.

In one' desirable arrangement there are two pairs of shoes: a pair ofmain shoes, preferably arranged to anchor at their, op-

posite ends when the drum is turning in opposite directions, and a pairof floating servo shoes, each arranged to force one of thema-in shoesagainst the drum. Importalit features of novelty relate to the ar--rangement of the anchoring abutments,shoepositioning stops, etc., tosecure the maximum effectiveness ofthe shoes.

The above and other objects and featiires of the invention will beapparent from the following description of one illustrative embodimentshown in the accompanying drawing, in which:-.

The figure is a vertical section through the brake, just. inside thehead of the drum,

showing the shoes in outside elevation.

The brake, in the form illustrated, includes.

a rotatable drum '10,"h'aving at its op'en'side a suitable "stationary;support or backingplatel2. On the backing plate are arrange theanchoring abutments for the shoes, four abutments-M, 16, 18, and 20being shown.

On opposite sides of the drum are arranged a pair of main brake shoes 22and 24.

When the brake is applied with the 'drum turning clockwise, shoe22anchors on abut-r ment 16 and shoe 24 on abutment 20; when the drum isturning counterclockwise, shoe 22 anchors on abutment 14 and shoe 24 onabutment 18.

Between the ends of the main shoes, and

therefore acting on the same zone of the drum, are servo shoes 26 and28. At each end of each servo shoe is a part '30, which is projectable'past the corresponding abutment to engage one or the other of the mainshoes. When the drum is turning clockwise, servo shoe 26 forces shoe 22against thedrum and against abutment-16, while servo shoe 28 forces shoe24 ag ainst the drum and against abutment 20. When the drum is turningcounter-clockwise, servo shoe 26 forces shoe 24 against the drum andagainst abutment 18, while servo shoe 28 forces shoe 22 againstthe drumand against abutment 14.

1926. Serial No. 100,287.

The servo shoes are forced apart against the drum to apply the brake bymeans such 7 as linkage including a double lever 32 on a shaft 34'floating in a slot 36 in the backing plate. At its upper end lever 32 ispivotally connected to shoe 26; at its lower end, it is pivotallyconnected to a thrust link 38 which in turn is pivoted to shoe 28.Turning shaft 34 counter-clockwise thus forces both shoes against thedrum.

The shoes are all urged away from the drum by return'springs 40, againstsuitable stops 42. Each stop may be arranged opposite one of the fourabutments, so that it IS engaged by the adjacent ends of two of theshoes.

While one illustrative embodiment has tional plurality of shoes,partforced against the drum by one servo .Shoeand part by the other andanchoring at opposite ends when the drum is turning in oppositedirections.

2. A brake comprising, in combination, a

drum, :1 pair of servo shoes engageable with opposite. sides 'of thedrum, and an. additional plurality of shoes, part forced against thedrum by. one servo shoe and part by the other, the part forced againstthe drum by eachone of the servo shoes When the drum is turning in onedirection being forced against the drum by the other. of the servo.

- shoes when the drum .is turning in the opposite direction.

3. A brake'comprising, in combination, a drum, a pair of servo shoesengageable with opposite sides of the drum, and an additional pluralityof floating shoes each an-' clioring at one end when the drum is turningin one direction and at the other end when the drum is turning in theother direction, and part forced against the drum by one servo shoe andpart by the other.

' 4. A brake comprising, in combination, a drum, a pairof ,servo shoesengageable with opposite sides of the drum, and, an additional pluralityof floating shoes each anchoring at one end when the drum is turn--ing'in one direction and at the otherend when the'drum is turning in theother direction, and part forced against the drum by one servo shoe andpart by the other, the.

part forced against the drum by each one of the servo shoes when thedrum is turning in one direction being forced against the drum by theother of the servo shoes when the drum is turning in the oppositedirecthe servo shoes'in opposite directions against opposite sides ofthe drum andfor causing each servo shoe to force one of the main shoesagainst the drum, the servo shoes being arranged between opposite endsofthe main shoes.

-6. A brake comprising, in combination, a drum, a pair of floating mainshoes engageable with the drum and anchoring. at either end, a pair ofservoshoes engageable with the drum, and means for forcing the servoshoes in opposite directions against opposite sides of the drum and forcausing each servo shoe to force one of the main shoes against the drumwhen the drum is turning in one direction and the other main shoeagainst the drum when the drum is turning in the opposite direction.

7. A brake comprising, in combination, a drum, main'and servo shoes alldisconnected from each other and all engageable with the same zone ofthe drum, and means for forcing the servo shoes against the drum andpermitting them to move with the drum to apply the main shoes.

8. A brake comprising, in combination, a drum, main and servo shoes alldisconnected from each other and all engageable with the same zone ofthe drum, and means for forcing the servo shoes in opposite directionsagainst diametrically-opposite portions of the drum and permitting themto move with thedrum to apply the main shoes.

9. A brake comprising, in combination, a drum, a plurality of'abutmentsspaced about the drum, main shoes between the abutments and arranged toanchor thereon at their opposite ends when the drum is turning inopposite directions, and servo shoes engageable with the drum and eachof which forces one of the main shoesagainst the drum. 7

10. A brake comprising, in combination, a drum, a plurality of abutmentsspaced about the drum, main shoes between the abutments and arranged .toanchor thereon at their opposite-ends when the drum is turning inopposite directions, and servo shoes engageable with the drum and eachof which forces one of the main shoes against the drum when the drum isturning in one direction and the other of the main shoes against thedrum when the drum is turning in the other direction.

11. A brake comprising, in combination a drum, a plurality of abutmentsspacer; about the drum, main shoes between the abutments and arranged toanchor thereon at their opposite ends when'the drum is turning inopposite directions, and servo shoes engageable with the same zone ofthe surface of the drum as the main shoes, and eachof which forces oneof the main shoes against the drum.

12. A brake comprising, in combination, a drum, at least one mainfloating shoe within the drum, an. abutment at each end ,of

the main shoe on which said shoe may anchor, and a pair of servo shoesat opposite ends of the 'main I shoe and disconnected I therefrom andeach of which forces the main shoe. against the drum when it anchorsagainst the abutment at the opposite end.

four fixed anchoring abutmentson at least part of which said meansanchors when the brake is applied, and a servo shoe between two of theabuments having at each end a part projectable past the correspondingabutment to apply the friction means without engagement of the servoshoe with said abutment.

14. A brake comprising, in combination, a drum, friction means withinthe drum, four fixed anchoring abutments on at least part of which saidmeans anchors when the brake is applied, a servo shoe between two of theabutments having at each end a part projectable past the correspondingabutment to apply the friction means without engagement of the servoshoe with said abutment, and a stop opposite each of said two abutmentsand on which the adjacent ends of the servo shoe and the friction meansrest when the brake is not applied.

15. A brake comprising, in combination, a drum, two-pairs of abutmentswithin the drum, a pair of main shoes, one between each pair ofabutments, apair of servo shoes arranged to force the main shoes againstthe drum, and a stop opposite each abutment, each stop supporting inidle position the adjacent ends of two of the shoes.

16. A brake comprising, in combination, a drum, two pairs of abutmentswithin the drum, a pair of main shoes,'one between each pair ofabutments, a pair of servo shoes arranged to force the main shoesagainst the drum, a stop opposite each abutment, each stop supporting inidle position the adjacent ends of two of the shoes, and a spring actingon each shoe and urging it against two of the stops.

17. A brake comprising, in combination, a drum, a pair of servo shoesengageable -with diametrically opposite sides of. the

I r 1,820,921 a 3 drum, means connecting the servo shoes and drum, alinkage connecting the servo shoes operable to force them apart againstthe and operable to force them apart against 10 drum, and a pair of mainshoes, 'each arthe drum, and "a pair of main shoes, each ranged to beforced against the drum by one arranged to be forced against thedrum by5 of the servo shoes. one of the servo shoes.

18. A brake comprising, in combination, In testimony whereof, I havehereunto a drum, a pair of servo shoes engageable signed my name. I withdiametrically opposite sides of the ROY S. SANFORD.

